What Is SOA?

SOA--Service Oriented Architecture--is merely an architecture style. You can think of it as a catalog of architectural concepts or as a programming model.

In an SOA architecture, all functions are provided as services assembled through an Enterprise Service Bus (ESB). This provides an unprecedented new level of flexibility in deploying and reusing services.
When SOA is implemented, existing information systems can be seen as services providing business functions. These functions are easily integrated because they provide clearly defined interfaces and can be accessed via standardized transport protocols.
There are two fundamental SOA elements to discuss:

• Interoperability concerns “window” business services, such as entering a command (which any Internet buyer has already used). Users must be able to communicate easily with the company’s outside Internet Provider.
• Re-use is particularly important for small, frequently consumed singular services such as a calculation, a database rule, access verification, LDAP access, etc. These elements remain relatively internal to the company, but are used by a number of “local” business services. Some of these services, such as user management, can make up an infrastructure service layer.

Why Migrate to an SOA ?

This architecture is a logical evolution for all existing Web architectures. What makes it new and original is that it takes existing applications into account. Already-existing applications can be extremely wide-ranging, and users want to take advantage of what they already have.
The Enterprise Bus, or ability to make applications communicate with each other in a standardized way, is particularly attractive because it develops application interoperability. Standardization is the wave of the future.

Imagine: a new partner is welcomed into your organization. You can hook up your command posts and billing systems almost instantaneously, and the efficiency gains for your organization will be immediately obvious. Imagine: integrating new CRM software. It is delivered and uses Web Services to plug itself into existing management elements.
Result: No more double entries, no more interface program development, and overall Information System (IS) coherence with minimal effort.

ETL/EAI tools have already shown the way in this field. However, SOA goes much further--rather than transferring/transforming data from one system to another, SOA connects processes. The challenge is to make your IT communicate. With standardization of network communications, where TCP/IP completely dominates the entire planet, it is time for applications to standardize access to the services they provide.

SOA and the System i 

To migrate an System i to SOA architecture, the essential first step is to use ILE (Integrated Language Environment). Only ILE allows implementation of the basic principle of SOA: code modularity. Only ILE will let you mix native RPG or COBOL with Web technologies.
What’s more, you can convert any ILE program into a Web service in the WDSC environment. Once your business functions are developed, it is simple to make them Web accessible.

Where do we begin?

How can you migrate to an SOA architecture when your IS is primarily made up of large applications that are not easily opened up to the outside? We strongly advise our clients to take a pragmatic approach. This means starting with a specific functional project that will quickly provide genuine added value to your IT. For example, this can be the opportunity to enter a new client’s information via the Web. This function can be made available to users through a Web site, and then simultaneously feed all the projects that need it. Starting with a case like this one, you will need to isolate all the new client entry functions and transform them into a single Web service. It’s vital to have a specific project to integrate the specific technical characteristics of an SOA and redefine your programming standards.
The ARCAD Software team can provide you with all the technical expertise you’ll need to get your foot in the door. For more information, refer to the Services page on our Website.

SOA and ARCAD Software Suites

There are three ARCAD tools to help businesses integrate SOA:

• The ARCAD-Open Repository is an in-depth knowledge base of the existing IS. This is where the system’s legacy and change memory is located.
• ARCAD-Observer is involved in maintenance and transfer procedures for technical knowledge of the existing IS.
• ARCAD-Skipper allows easier integration of the new technology needed to establish SOA.

ARCAD Open Repository

A central repository is indispensable for any SOA project. Code modularity automatically means an increase in new components-and not all of these components work on the same platforms. How can you get an overall picture of all these applications? The ARCAD Repository allows referencing of any component type, whether on a System i or deployed on a server, and whether you are handling components from System i, UNIX, Linux or Windows.
The other fundamental aspect of the ARCAD Repository is that it collects all inter-component relationships (or cross-references, as developers call them). This is an essential information source to keep control of application developments.

The ARCAD-Observer Suite

Naturally, the initial step of an SOA procedure is to analyze the existing system. You will need to perform an inventory of the functions already contained within the IS that can be transformed into services. The ARCAD-Observer application-mapping suite is unquestionably the ideal tool for this task. Observer offers a battery of varied tools that let you delve into applications’ internal architecture to understand all the links.
You can then start by reconstituting a data model, which is a fundamental basis from which you will work back through procedures to isolate management rules. ARCAD-Observer has all these elements: it automatically reconstitutes calling program cascades using calling chains. Each field can be followed from component to component, all the way into the source code. The source code analyzer then helps you present the internal logic of all your programs.
At a more macro level, you can use the macroscopic views to get a broader picture of your IS’s major functional areas.

The ARCAD-Skipper Suite

ARCAD-Skipper is a multi-platform software configuration management suite. In combination with the ARCAD Repository, Skipper allows rigorous, coherent organization of all software component change processes, regardless of their original platform. The biggest advantage is its ability to deploy components onto diverse servers using a single process. In addition to these "traditional functions, ARCAD-Skipper is a structuring system that painlessly integrates new development technologies. Skipper is particularly focused on the two bases of SOA: ILE and SQL.